A Patent Document 1 listed below discloses a pneumatic tire whose stiffness against a lateral input force is improved by increasing a volume of rubber by increasing a minimum curvature radius of an outside curved portion of an inner surface of a groove.
As shown in FIG. 4, in the pneumatic tire T10 disclosed in the Patent Document 1, in a lateral cross-sectional view of a circumferential main groove 100, an inequality (a minimum curvature radius R1 of an outside curved portion 101)>(a minimum curvature radius R2 of an inside curved portion 102) is satisfied. In addition, in the lateral cross-sectional view, with respect to angles (groove wall angles) of groove wall surfaces 103, 105 to a normal line(s) N of a tread surface 106 (hereinafter, this is called as a tread normal line) at border edges between the groove wall surfaces 103, 105 and the tread surface 106, an inequality (the groove wall angle α on an installation outer side)>(the groove wall angle β on an installation inner side) is satisfied. The “installation outer/inner side” is an outer/inner side with respect to a body of a vehicle when the tire T10 is installed on the vehicle. The “outside/inside curved portion” is similar thereto. According to these configurations, reduction of a lateral input force at edges of land portions (blocks and ribs) 104 is restricted and thereby a larger lateral force is generated, so that dynamic performance and handling stability are improved.